I think Tucker and I are both saying climate is changing because the science is clear: climate has changed many times over 4 billion years. We also agree in principle human activity could have an impact on climate. However we are asking for numbers. I think that is the nature of science and statistics to test an assertion against empirical evidence. I don’t think that’s a logical fallacy. Your example of heaps is an issue of definition — definitely not the same as asking for a prediction of change in degrees Centigrade over a specified time period and a fraction attributing how much is due to human activity. Maybe we just agree to disagree.